The present subject matter relates generally to methods for the removal of oxygenates from naphtha. More specifically, the present subject matter relates to the methods for the removal of oxygenates from petrochemical naphtha by water wash and subsequent treatment with an adsorbent.
The hydrocarbons used in industry should be produced as pure as possible without the presence of oxygen containing organic compounds such as oxygenates. Oxygenates are compounds with at least one hydrocarbon backbone and a low content of oxygen. Oxygenate compounds are valuable materials, but in combination with hydrocarbons, they are unsuitable for use in various petroleum conversion processes where catalysts are employed. The straight run naphtha from the upstream crude column is usually contaminated due to processing of different crude slates. The contaminants present in the straight run naphtha generally includes oxygenates such as alcohol, ketones, aldehydes and ether that are known to cause problems in a refinery. Oxygenate compounds found in the crude naphtha create problems such as catalyst deactivation or fouling in the downstream processing. The transport of the contaminated material to other tanks has a higher risk of cross contamination for the remaining product storage tanks. Therefore, there is a need to remove the oxygenate contaminants from the straight run naphtha and eliminate the associated problems in downstream processing.
Conventionally, oxygenates in the crude run naphtha are removed by water-wash. However, water washing the straight run naphtha does not remove all of the oxygenates in order to meet the required specification of the petrochemical grade. There is a need for an improved process to remove oxygenates from crude naphtha for commercial use.
Those skilled in the art are well versed in use of adsorbents for removal of oxygenates from the petrochemical naphtha. In typical operation of an adsorptive oxygenate removal unit, the system uses two or more beds wherein one bed is operating in adsorption mode and the other operating in regeneration mode. But the adsorbent beds need to be replaced continuously for efficient removal of oxygenates and that may result in high energy costs. Generally, a liquid regenerant is externally added to the adsorbent column to regenerate the adsorbent bed. This can further result in additional cost for effective operation of the adsorbent bed. Therefore, there is need for an improved and more economical method for removing oxygenates from petrochemical naphtha.